Apparatus for recovery and use of waste thermal energy

Abstract

Energy recovery apparatus for recovering and using thermal energy comprises multiple series of shape memory elements having decreasing transformation temperatures from one element to the next in the direction of a heating fluid to extract heat over a range of fluid temperatures to effect a shape change of each element. Cooling fluid is flowed alternately through each series of elements to cool the elements and effect another shape change. The cooling fluid exiting a preceding series of elements is used as the heating fluid of the next series of elements to extract further heat indirectly from the original heating fluid. The shape changes of the elements are converted to mechanical work.

We claim: 
     
       1. Energy recovery apparatus for recovering and using thermal energy, comprising: a) means for directing a heating fluid along a first series of shape memory elements having a decreasing transformation temperature range from one element to the next in the direction of flow of a heating fluid such that thermal energy is extracted from the heating fluid over a range of fluid temperatures to heat said elements sufficiently to effect a shape change of said elements,   b) means for directing a first cooling fluid along said first series of heated shape memory elements in a direction opposite to the direction of flow of said heating fluid such that thermal energy is extracted from said elements over a range of temperatures to cool said elements sufficiently to effect another shape change of said elements,   c) means for directing the heated first cooling fluid from said first series of shape memory elements along a second series of shape memory elements having a decreasing transformation temperature range from one element to the next in the direction of flow of said heated first cooling fluid such that thermal energy is extracted from the heated cooling fluid over a range of fluid temperatures to heat said elements sufficiently to effect a shape change of said elements,   d) means for directing a second cooling fluid flow along said second series of heated shape change memory elements in a direction opposite to the direction of flow of said heated first cooling fluid such that thermal energy is extracted from said elements over a range of temperatures to cool said elements sufficiently to effect another shape change of said elements, and   e) means operably coupled to said shape memory elements for converting said shape changes thereof to mechanical work.   
     
     
       2. The apparatus of claim 1 wherein said means for directing said heating fluid along said first series of shape memory change elements comprises means for conveying a waste heating fluid along said first series of said elements. 
     
     
       3. The apparatus of claim 2 wherein said waste heating fluid comprises exhaust gases from an internal combustion engine. 
     
     
       4. The apparatus of claim 1 wherein said first cooling fluid comprises ambient air flowed along said first series of shape memory elements. 
     
     
       5. The apparatus of claim 1 wherein said second cooling fluid comprises ambient air flowed along said second series of shape memory elements. 
     
     
       6. The apparatus of claim 1 wherein said first series of shape memory elements comprise tubular members through which said heating fluid and said first cooling fluid are alternately flowed. 
     
     
       7. The apparatus of claim 1 wherein said second series of shape memory elements comprise tubular members through which said first heated cooling fluid and said second cooling fluid are flowed. 
     
     
       8. Energy recovery apparatus for recovering and using thermal energy, comprising: a) means for directing a waste heating fluid along a first series of shape memory elements having a decreasing transformation temperature range from one element to the next in the direction of flow of said heating fluid such that thermal energy is extracted from the heating fluid over a range of fluid temperatures to heat said elements sufficiently to effect a shape change of said elements,   b) means for exhausting said heating fluid to ambient when said heating fluid reaches a near-ambient temperature,   c) means for directing a first cooling fluid along said first series of heated shape memory elements in a direction opposite to the direction of flow of said heating fluid such that thermal energy is extracted from said elements over a range of temperatures to cool said elements sufficiently to effect another shape change of said elements,   d) means for directing the heated first cooling fluid from said first series of shape memory elements along a second series of shape memory elements having a decreasing transformation temperature range from one element to the next in the direction of flow of said heated first cooling fluid such that thermal energy is extracted from the heated cooling fluid over a range of fluid temperatures to heat said elements sufficiently to effect a shape change of said elements,   e) means for exhausting said heated first cooling fluid to ambient when it reaches a near-ambient temperature,   f) means for directing a second cooling fluid along said second series of heated shape change memory elements in a direction opposite to the direction of flow of said heated first cooling fluid such that thermal energy is extracted from said elements over a range of temperatures to cool said elements sufficiently to effect another shape change of said elements, and   g) means operably coupled to said shape memory elements for converting said shape changes thereof to mechanical work.   
     
     
       9. The apparatus of claim 8 wherein said waste heating fluid comprises exhaust gases from an internal combustion engine. 
     
     
       10. The apparatus of claim 8 wherein said first cooling fluid comprises ambient air flowed along said first series of shape memory elements. 
     
     
       11. The apparatus of claim 8 wherein said second cooling fluid comprises ambient air flowed along said second series of shape memory elements. 
     
     
       12. The apparatus of claim 8 wherein said first series of shape memory elements comprise tubular members through which said heating fluid and said first cooling fluid are alternately flowed. 
     
     
       13. The apparatus of claim 8 wherein said second series of shape memory elements comprise tubular members through which said first heated cooling fluid and said second cooling fluid are flowed. 
     
     
       14. A method of recovering and using thermal energy, comprising: a) directing a heating fluid along a first series of shape memory elements having a decreasing transformation temperature range from one element to the next in the direction of flow of said heating fluid such that thermal energy is extracted from the heating fluid over a range of fluid temperatures to heat said elements sufficiently to effect a shape change of said elements,   b) directing a first cooling fluid along said first series of heated shape memory elements in a direction opposite to the direction of flow of said heating fluid such that thermal energy is extracted from said elements over a range of temperatures to cool said elements sufficiently to effect another shape change of said elements,   c) directing the heated first cooling fluid from said first series of shape memory elements along a second series of shape memory elements having a decreasing transformation temperature range from one element to the next in the direction of flow of said heated first cooling fluid such that thermal energy is extracted from the heated cooling fluid over a range of fluid temperatures to heat said elements sufficiently to effect a shape change of said elements,   d) directing a second cooling fluid flow along said second series of heated shape change memory elements in a direction opposite to the direction of flow of said heated first cooling fluid such that thermal energy is extracted from said elements over a range of temperatures to cool said elements sufficiently to effect another shape change of said elements, and   e) converting said shape changes of said elements to mechanical work.